Contralateral sensory neglect follows unilateral lesions in the vicinity of the lateral hypothalamus of rats. The purpose of the proposed research is 1) to determine whether such sensory neglect can be demonstrated if the test stimuli are used as discriminative stimuli for an instrumental response maintained by positive reinforcement and requiring a minimum of voluntary motor activity; 2) to determine whether this test procedure can be used as an objective, quantitative performance measure of sensory neglect (and other possible deficits); 3) to explore the feasibility of investigating neurophysiological changes associated with sensory neglect by electrical recording techniques in chronically prepared animals performing in this testing situation.